Dock seals are commonly used in association with loading docks to provide a seal between the end of a truck body parked in front of the loading dock and the dock. The use of a dock seal is particularly important when a loading operation is being carried out at a cold storage warehouse to prevent warmer ambient air from entering the warehouse. Conversely, in cold weather climates, it is desirable to provide a seal between the truck body and the dock to prevent the colder ambient air from entering the warehouse or other facility.
The conventional dock seal includes a pair of resilient pads, commonly made of foam plastic material, which are mounted alongside the doorway in the loading dock. In addition, a header formed of resilient material can also be mounted along the upper edge of the doorway, connecting the upper ends of the two side pads. In order to accommodate truck bodies of varying widths, the side pads of the dock seal have a substantial width, and as a truck backs toward the loading dock, the rear end of the truck body will engage and compress the pads to provide a seal between the truck body and the dock.
However, the use of the conventional dock seal has certain disadvantages. The side pads of the dock seal will normally protrude inwardly of the sides of the truck body, thereby limiting access to the truck body and complicating end loading and unloading operations. Further, the edges of dock seal pads projecting into the truck body can be contacted by a fork lift truck moving between the dock and the truck bed, frequently causing damage to the pads.
It has also been found that when the truck is provided with an overhead door, the truck will normally back toward the dock with the door closed. With the use of the conventional dock seal, the handle for the overhead door will usually be embedded within the compressed side panel of the dock seal. The workman must then attempt to locate the handle and pull the handle upwardly against the force of the compressed seal. This not only is difficult, but in some instances the handle can rip the fabric covering of the dock seal.
As an alternate sealing mechanism, dock shelters have also been utilized. The conventional dock shelter, includes a pair of side panels which are mounted on the dock alongside the doorway and are adapted to be moved into contact with the outer side wall of the truck body to provide a weather seal.
A dock shelter has the advantage that there is no encroachment on the interior of the truck body, but a dock shelter is normally more complicated in operation and considerably more expensive than a dock seal.
As a further disadvantage, the conventional dock shelter will not provide a complete seal when the truck body has outwardly swinging doors. In normal practice, the outwardly swinging doors of the truck body are swung to the open position, against the sides of the truck body, before the truck backs toward the loading dock. With the doors swung open, the side panels of the dock shelter will engage the open doors, as opposed to engaging the side wall of the truck body, and no seal is provided for the gap between the outwardly swung doors and the truck body. There can be considerable air movement through this gap which destroys the basic sealing objective.